(a) Field of the Invention
The present invention relates to a cooperative caching method and a contents providing method using a request apportioning device in a clustered application architecture.
(b) Description of the Related Art
In general, regarding a clustered application architecture, a load balancer or a domain name server (DNS) uses a load balancing algorithm appropriate for a service characteristic, that is, a scheduling method based on a round robin, least connection, hash, or weight value method to balance a load so that the load may not be heavily provided to a specific lower cache server in a cache cluster, and to request contents from a random cache server.
In this instance, the cache server having received a contents provision request may have the corresponding contents or not, and when it does not have them, it caches them through cooperative caching.
The cooperative caching process allows the cache servers in the cache cluster to share contents caching.
To perform the cooperative caching process, in the prior art, a cache server having no contents inquires of other cache servers in the same cache cluster whether they have corresponding contents to find the cache server that has them, and it requests the contents from the corresponding cache server. When none of the other cache servers in the same cache cluster have the corresponding contents, it downloads them from a source server and keeps them.
However, the conventional cooperative caching method performs cooperation for sharing contents within a short time when there are not many cache servers in the cache cluster, but the method requires much time for finding a cache server that has the contents when there are many cache servers. As a result, when there are many cache servers in the cache cluster, the time for providing contents is increased according to the prior art.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.